Films for pole-tip recession adjustment

ABSTRACT

A sensor comprises a transducer portion including a semi-permanently deformable portion. A deformation of the semi-permanently deformable portion in response to an activation energy deforms the transducer portion. The deformation is retained after the activation energy is removed. In another embodiment of the invention, a transducer comprises a body having an active element, a magnetostrictive element and a magnet having a magnetic field. The magnetic field causes a deformation of the magnetostrictive portion thereby adjusting the position of the active element.

CROSS REFERENCE TO RELATED APPLICATION

This is a continuation application of application Ser. No. 10/465,756entitled “Films For Pole-Tip Recession Adjustment” and filed Jun. 19,2003 by Jeremy Adam Thurn, et al., now pending.

BACKGROUND OF THE INVENTION

The present invention relates to an air bearing slider for use in a datastorage device such as a disc drive. More particularly it relates to anair bearing slider capable of operating at ultra-low flying heights.

Air bearing sliders have been extensively used in magnetic disc drivesto appropriately position a transducing head above a rotating disc. In adisc drive, each transducer “flies” just a few nanometers above arotating disc surface. The transducer is mounted in a slider assemblywhich has a contoured surface. An air bearing force is produced bypressurization of the air as it flows between the disc and slider and isa consequence of the slider contour and relative motion of the twosurfaces. The air force prevents unintentional contact between thetransducer and the disc. The air bearing also provides a very narrowclearance between the slider transducer and the rotating disc. Thisallows a high density of magnetic data to be transferred and reduceswear and damage.

In most high capacity storage applications, when the disc is at rest,the air bearing slider is in contact with the disc. During operation,the disc rotates at high speeds, which generates a wind of airimmediately adjacent to the flat surface of the disc. This wind actsupon a lower air bearing surface of the slider and generates a liftforce directing the slider away from the disc and against a load beamcausing the slider to fly at an ultra-low height above the disc.

In negative pressure sliders, the wind also acts upon a portion of theair bearing surface of the slider to generate a suction force. Thesuction force counteracts the lift force by pulling the slider backtoward the surface of the disc. A slider is typically mounted on agimbal and load beam assembly which biases the slider toward therotating disc, providing a pre-load force opposite to the lift forceacting on the air bearing surface of the slider. For the slider tomaintain the ultra-low flying height above the surface of the disc, thelift force must be balanced with the pre-load and suction forces.

As disc storage systems are designed for greater and greater storagecapacities, the density of concentric data tracks on discs is increasing(that is, the size of data tracks and radial spacing between data tracksis decreasing), requiring that the air bearing gap between thetransducing head carried by the slider and the rotating disc be reduced.One aspect of achieving higher data storage densities in discs isoperating the air bearing slider at ultra-low flying heights.

However, shrinking the air bearing gap and operating the slider atultra-low flying heights has become a source of intermittent contactbetween the transducing head and the disc. Furthermore, when a discdrive is subjected to a mechanical shock of sufficient amplitude, theslider may overcome the biasing pre-load force of the load beam assemblyand further lift away from or off the disc. Damage to the disc may occurwhen the slider returns to the disc and impacts the disc under thebiasing force of the load beam. Such contact can result in catastrophichead-disc interface failure. Damage to the disc may include lost orcorrupted data or, in a fatal disc crash, render the disc driveinoperable. Contact resulting in catastrophic failure is more likely tooccur in ultra-low flying height systems. Additionally, intermittentcontact induces vibrations detrimental to the reading and writingcapabilities of the transducing head.

For the disc drive to function properly, the slider must maintain theproper fly height and provide adequate contact stiffness to assure thatthe slider does not contact the disc during operation. Also, the airbearing slider must have enhanced take-off performance at start up tolimit contact between the slider and the disc. Such contact would causedamage to the slider during take-off and landing of the slider.

Air bearing sliders typically possess three primary degrees of movement,which are vertical motion, pitch, and roll rotation. The movement isrelative to the gimbal and load beam associated with three appliedforces upon the slider defined as pre-load, suction, and lift force.Steady state fly attitude for the slider is achieved when the threeapplied forces balance each other. A typical air bearing slider has ataper or step at its leading edge to provide for fast pressure buildupduring takeoff of the slider from a resting position to a flyingaltitude above the disc. Air bearing sliders have a trailing edge atwhich thin film transducers are deposited. Typically, the air bearingsurface includes longitudinal rails or pads extending from the leadingedge taper toward the trailing edge. The rail design determines thepressure generated by the slider. The pressure distribution underneaththe slider determines the flying characteristics, including flyingheight and pitch and roll of the slider relative to a rotating magneticdisc. Other characteristics that are affected by the configuration ofthe air bearing surface of a slider are takeoff velocity, air bearingstiffness, and track seek performance.

Flying height is one of the most critical parameters of magneticrecording. As the average flying height of the slider decreases, thetransducer achieves greater resolution between the individual data bitlocations on the disc.

Therefore, it is desirable to have the transducers fly as close to thedisc as possible.

In a conventional air bearing slider, the slider body is formed from asubstrate wafer of conductive ceramic material. On this substrate, athin film of insulating material is deposited, and a metallic transduceris built therein, by a process such as sputtering. The transducer, whichtypically includes a writer portion for storing magnetically-encodedinformation on a magnetic media and a reader portion for retrieving thatmagnetically-encoded information from the magnetic media, is formed ofmultiple layers successively stacked upon the substrate. The volume ofthe transducer is typically much smaller than the volume of thesubstrate.

The wafer with transducers formed thereon is then cut into bars, and acut edge of each bar is lapped to form an air bearing surface. Thelayers of the transducer, which include both metallic and insulatinglayers, all have different mechanical and chemical properties than thesubstrate. These differences in properties affect several aspects of thetransducer. First, the different materials of the slider will be lappedat different rates. Because of the difference in hardness or lappingdurability of the wafer substrate material, the thin film insulatingmaterial, and the transducers, the lapping operation results indifferential recession of the materials at the air bearing surface.

Thus, when an air bearing surface of a slider is lapped during itsfabrication, differing amounts of the different materials will beremoved B resulting in the slider having a uneven air bearing surface.The recession of a particular component is defined as the distancebetween the air bearing surface of the ceramic substrate and the airbearing surface of that component.

Commonly, a greater amount of the metallic layers of the transducer willbe removed during the lapping process than will be removed from theslider body substrate. Thus, this lapping process results in a Pole TipRecession (PTR) of the metallic layers of the transducer with respect tothe slider body substrate.

Additionally, the insulating material will often recede at an evengreater rate than the transducer, leading to material recession thatresults in a discernable offset at the interface of the insulatingmaterial and the slider body substrate material. The offset prevents thetransducer from flying as close to the surface of the magnetic disc aswould otherwise be possible.

Further, the differing mechanical and chemical properties of thesubstrate and transducer layers further affect the air bearing surfaceduring operation of the transducing head. As the magnetic data storageand retrieval system is operated, the transducing head is subjected toincreasing temperatures within the magnetic data storage and retrievalsystem. In addition, a temperature of the transducing head itself, or apart thereof, may be significantly higher than the temperature withinthe magnetic data storage and retrieval system due to heat dissipationcaused by electrical currents in the transducer.

During operation of the magnetic data storage and retrieval system, thetransducing head is positioned in close proximity to the magnetic media.A distance between the transducer and the media is preferably smallenough to allow for writing to and reading from a magnetic medium havinga large areal density, and great enough to prevent contact between themagnetic media and the transducer. Performance of the transducer dependsprimarily on this distance.

Thus, a need exists for an air bearing slider design which achieves aconstant, ultra-low transducer flying height, despite the obstacles ofdifferential mechanical recession.

BRIEF SUMMARY OF THE INVENTION

The present invention is a sensor, which comprises a transducer portionincluding a semi-permanently deformable portion. A deformation of thesemi-permanently deformable portion in response to an activation energydeforms the transducer portion. The deformation is retained after theactivation energy is removed. In another embodiment of the invention, atransducer comprises a body having an active element, a magnetostrictiveelement and a magnet having a magnetic field. The magnetic field causesa deformation of the magnetostrictive portion thereby adjusting theposition of the active element.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a top perspective view of a disc drive.

FIG. 2 is a side elevation view of a slider flying above a disc surface.

FIG. 3 is an enlarged side elevation of a rear portion of a sliderincorporating a film of deformable material.

FIG. 4 a is a side elevation view of the slider of FIG. 3 afteractivation of the film in one embodiment.

FIG. 4 b is a side elevation view of the slider of FIG. 3 afteractivation of the film in another embodiment.

FIG. 5 is an enlarged side elevation of another embodiment of a rearportion of a slider incorporating a film of deformable material.

FIG. 6 is a side elevation view of the slider of FIG. 5 afterdeformation of the film.

FIG. 7 is a side elevation view of an enlarged portion of a sliderwherein the pole tip protrudes from the head stack but does not recedefrom the slider body.

FIG. 8 is a side elevation view of the slider of FIG. 7 after activationof the deformable material.

DETAILED DESCRIPTION

FIG. 1 shows a top perspective view of a disc drive 12, which includes avoice coil motor (VCM) 13, actuator arm 14, suspension 16, flexure 18,slider 20, head mounting block 22, and disc 24. Slider 20 is connectedto the distal end of suspension 16 by flexure 18. Suspension 16 isconnected to actuator arm 14 at head mounting block 22. Actuator arm 14is coupled to VCM 13. Disc 24 has a multiplicity of tracks 26 androtates about axis 28. During operation of disc drive 12, rotation ofdisc 24 generates air movement which is encountered by slider 20. Thisair movement acts to keep slider 20 aloft a small distance above thesurface of disc 24, allowing slider 20 to fly above the surface of disc24. VCM 13 is selectively operated to move actuator arm 14 around axis30, thereby moving suspension 16 and positioning the transducing head(not shown) carried by slider 20 over tracks 26 of disc 24. Properpositioning of the transducing head is necessary for reading and writingdata on concentric tracks 26 of disc 24.

FIG. 2 is a side elevation view of a slider flying above a disc surface.Direction 32 is designated as a forward or leading direction, anddirection 34 is designated as a rearward or trailing direction. Slider20 includes slider body 36, which is composed of a wafer of anelectrically-conductive, ceramic substrate material such as Al₂O₃—TiC,AlTiC, TiC, Si, SiC, ZrO₂ or other composite materials formed ofcombinations of these materials.

Transducer portion 38 comprises electrical insulating head stack 40.Interface 42 defines the intersection of the different materials ofslider body 36 and transducer portion 38. Head stack 40 is preferablyformed of an insulating material, such as Al₂O₃, AlN, SiO₂, Si₃N₄, SiC,or SiO₀₋₂N_(0-1.5).

Generally, the insulating material for head stack 40 is selected toclosely match the chemical and mechanical properties of the materialused for slider body 36. For example, an Al₂O₃ head stack 40 is commonlyused in conjunction with an AlTiC slider body 36, since the twomaterials have similar coefficients of thermal expansion (CTE).Additionally, Al₂O₃ is preferred for head stack 40 because of the easeof planarization of the material.

FIG. 2 further shows transducer 44 and transducer pole tip 46. Magnetichead transducer 44 with pole tip 46 is formed of electrically conductivemetallized patterns embedded within head stack 40 of transducer portion38. Such metals, such as NiFe, typically have large CTEs. Because morethan one transducer 44 is typically formed within head stack 40, theinsulating properties of head stack 40 prevent transducers 44 fromshorting each other out during operation. Encapsulation of transducer 44within head stack 40 is achieved by chemical vapor deposition, aphotolithographic process, or another process used in integrated circuitmanufacturing.

FIG. 3 is an enlarged side elevation of a rear portion of one embodimentof a slider incorporating a film of deformable material. Transducer 44generally includes a reader 45 and a writer; the writer generallyincludes conductive coils 47, core fill 49, back via 51, shared poleextension 53, bottom pole 55 and top pole 57. The portions of bottompole 55 and top pole 57 which extend from head stack 40 are generallyreferred to as pole tip 46. Conductive coil 47 wraps around back via 51such that the flow of electrical current through conductive coil 47generates a magnetic field for the write operation.

Generally, the materials which make up slider body 36, head stack 40,and transducer 44 differ from each other in respect to their hardness orlapping durability. Usually, the material of transducer 44 is softerthan the material of slider body 36. Generally, the material of headstack 40, usually alumina, is softer than the material of transducer 44.These hardness differentials result in varying levels of materialrecession as the lapping process forms air bearing surface 48 on slider20 because the softer materials are removed at a higher rate than theharder materials. Subsequent slider processes, such as ion milling, canalso affect the variation and average levels of material recession. Airbearing surface 48 is formed on the face of slider 20 which opposes disc24. The present invention may be used on a symmetric or asymmetric,positive or negative pressure air bearing slider 20, for example.

Pole tip recession 50 and head stack recession 52 are illustrated inFIG. 3. Pole tip recession 50 is the difference in height between thebottom surface of pole tip 46 and the bottom surface of slider body 36.Head stack recession 52 is the difference in height between the bottomof head stack 40 and the bottom of slider body 36. Usually, pole tip 46protrudes from head stack 40. However, it is contemplated that in somecases, pole tip 46 may recede into head stack 40. Because of the pitchat which slider 20 flies, these recessions result in a mechanical closepoint 54 of slider 20 at interface 42. This pitch is exaggerated in FIG.3 for purposes of description. Mechanical close point 54 is the point onslider 20 which is the shortest distance from the surface of magneticdisc 24. This distance is the mechanical close point height 56. As canbe seen, pole tip fly height 58 is greater than mechanical close pointheight 56. In most cases, pole tip fly height 58 is up to about eightpercent greater than mechanical close point height 56.

Market demand for increasing hard drive recording density has resultedin a drastic decrease in head media spacing (pole tip fly height 58).Thus, it is preferable that the mechanical close point 54 of slider 20is at pole tip 46 (as will be discussed later with reference to FIG. 4).In that circumstance, transducer pole tip 46 would be very close to disc24, thereby resulting in greater recording capacity. An advantage ofplacing mechanical close point 54 at pole tip 46 is that theconfiguration improves flyability by decreasing the chance that slider20 will unintentionally contact disc 24, without a detrimental effect onrecording capacity.

The present invention adjusts the pole tip recession 50 of slider 20after pole tip recession-modifying slider processes such as lapping andion milling. This pole tip adjustment positions mechanical close point54 of slider 20 at pole tip 46 through the deformation of deformablematerial 60 embedded within head stack 40. Deformable material 60 ispreferably in the form of a film for ease of manufacture, but it iscontemplated that it may take other forms such as a mass of bulkmaterial in the form of a stud or another structure. In one embodiment,deformable material 60 is preferably deposited onto slider 20 by slidermanufacturing processes such as sputtering, cold pressing, and pulsedlaser deposition. In the embodiment illustrated in FIG. 3, deformablematerial 60 is preferably disposed in head stack 40 at interface 42;however, it is contemplated that deformable material 60 may be placedanywhere within or on head stack 40 or slider body 36.

Deformable material 60 is capable of undergoing a semi-permanent orpermanent deformation. The term “semi-permanent” includesmagnetostrictive changes in structure, plastic deformations, and phasetransformation induced deformations. Material 60 may be deformed by theapplication of an activating energy including magnetism, temperaturechange, pressure force and other forms of excitement. Plasticdeformations refer to those in which the deformed material retains itsdeformed configuration even after removal of the activation ordeformation energy. Phase transformation induced deformations are alsoconsidered semi-permanent; shape memory alloys (SMA) generally exhibitphase transformation induced deformations. Generally, SMAs are materialsthat are deformed at a low temperature and then changed back to theiroriginal undeformed condition at a higher temperature. This change ofshape is believed to result from a transformation from a martensitecrystal structure to an austenite crystal structure in a transformationtemperature range. As long as the temperature is such so that the SMAremains in one state, the form of the SMA is retained and does notchange, even upon removal of the activating energy. Magnetostrictivedeformations can be rendered semi-permanent where the deformedconfiguration of the material is maintained by the placement of apermanent or semi-permanent magnet in the vicinity of the deformablematerial. In the present invention, it is preferred that the deformationof deformable material 60 is semi-permanent rather than permanentbecause it may be desirable in some circumstances to reverse thedeformation and return deformable material 60 to its initial, undeformedconfiguration.

Elastic deformations are contrasted with semi-permanent deformationssuch as plastic deformations, phase transformation induced deformationsand magnetostrictive deformations. With elastic deformations, thedeformed material returns to its undeformed state upon removal of theactivation energy. Thus, with elastic deformations, the activationenergy must be continually applied to retain the material in itsdeformed configuration.

FIG. 4 a is a side elevation view of the slider of FIG. 3 afteractivation of the film in one embodiment. As shown in FIG. 4, deformablematerial 60 has been deformed so as to expand and push down upontransducer 44, thereby moving the bottom surface of pole tip 46 to aboutthe same level as the bottom surface of slider body 36. Thisdisplacement essentially eliminates the pole tip recession 50 shown inFIG. 3. Because of the pitch at which slider 20 flies, this displacementalso moves the mechanical close point 54 to the bottom surface of poletip 46. Accordingly, mechanical close point height 56 is the same aspole tip fly height 58. This configuration desirably results inincreased recording capacity and improved flyability. While FIG. 4 isillustrated with the pole tip recession being equal to zero, it is alsocontemplated that the pole tip recession may be simply reduced incomparison to FIG. 3, or the pole tip could be moved even furtherdownward, resulting in a slight pole tip protrusion with respect toslider body 36.

While deformable material 60 is illustrated as a film which expands onlyin the linear direction indicated by arrow 62, it is also contemplatedthat other depositions of deformable material may be used, includingmasses of bulk material distributed in other locations within and onslider 20. The deformable film 60 is deposited in head stack material 40during the processing of head stack 40. During the manufacture of slider20, deformable material 60 is activated, resulting in a semi-permanentchange in strain. The activation may be accomplished by a magneticfield, an applied voltage, surface heating using lasers, cooling, andthermal annealing, for example, or any combination thereof, depending onthe magnitude of strain change desired and the composition of shapememory alloy film 60. In some embodiments, the strain is semi-permanentbecause it may be reversed by exposing deformable material 60 to amagnetic field, voltage, or temperature different in magnitude orcharacter than that used to activate the film.

Where deformable material 60 grows in length in both directions alongarrow 62, a bump 66 of head stack material may form as the growth ofdeformable material pushes the material of head stack 40 in the upwardas well as the downward directions.

In one embodiment, deformable material 60 comprises a shape memorymaterial such as a shape memory alloy in the form of a film.Deformations of shape memory alloys are generally phase transformationinduced. Shape memory alloys are materials that are deformed at a lowtemperature and then changed back to their original undeformed conditionat a higher temperature. This change of shape is believed to result froma transformation from a martensite crystal structure to an austenitecrystal structure in a transformation temperature range. Common shapememory alloys include nickel alloys, such as nickel-titanium alloys, andcopper-zinc alloys.

Shape memory alloys include both one-way SMAs and two-way SMAs. One-waySMAs change shape as they are heated without the application of anexternal force. When one-way SMAs are cooled, however, an external forceis needed to reverse the shape change. Two-way SMAs change shape as theyare heated without the application of an external force. Two-way SMAsalso change shape as they are cooled without the application of anexternal force. Two-way SMAs are also referred to as reversible SMAs. Inthe present invention, the use of one-way, two-way SMAs, or both one-wayand two-way SMAs in a slider is contemplated. Transformationtemperatures of SMA thin films are dependent not only on the compositionof the material, but also on its history of thermal processing.Ferromagnetic SMAs are preferably used, including copper and iron basedalloys.

FIG. 4 b is a side elevation view of the slider of FIG. 3 afteractivation of the film in another embodiment. In an this embodiment,deformable material 60 comprises a magnetostrictive material, thedeformation of which is held semi-permanently by magnet 64. The size,location, angle and strength of magnet 64 is chosen to set the strain indeformable material 60 in order to displace pole tip 46 to a desiredlocation. In one embodiment, the coercivity of magnet 64 is at leastabout 500 Oe (oersted) greater than or less than a coercivity of theslider reader setting. In a preferred embodiment, magnet 64 is set to amagnetic field between about 2 and about 20 kOe to achieve a desiredstrain. Magnetostrictive materials deform upon exposure to a magneticfield. Examples of magnetostrictive materials includerare-earth-transition-metal (RE-TM) alloys. Particularly suitablemagnetostrictive materials for this invention includes those which areferromagnetic with high coercivity, highly magnetostrictive (i.e.,exhibit a relatively large deformation change per unit of appliedmagnetism), have a large Young's modulus, and compatibility with slidermanufacturing processes.

An example of a suitable magnetostrictive material is an alloy ofterbium, iron and dysprosium. In one embodiment, a seed layer isdeposited onto the forming head stack and a high-coercivity permanentmagnet 64 is formed on the seed layer. A layer of the magnetostrictivematerial 60 is sputtered onto the magnet and the film is crystallizedduring a high-temperature annealing process. The magnetization of magnet64 is set to achieve the desired magnetostriction effect. In anotherembodiment, a layer of magnetostrictive material 60 is deposited ontothe forming head stack, with or without the use of a seed layer. Magnet64 is then deposited on the magnetostrictive material 60.

In a preferred embodiment, the Young's modulus is at least about 20 Gpa.Both Young's modulus and magnetostriction are affected by compositionand crystal structure. For instance, some amorphous magnetostrictivematerials have a significantly lower magnetostriction than crystallineforms of those materials. Crystalline films of some magnetostrictivematerials can be obtained by annealing or deposition at elevatedtemperatures. The magnitude of PTR adjustment is expected to increasewith, individually, increasing volume of deformable material(accomplished by increasing film thickness, for example), increasingYoung's modulus and increasing magnetostriction or film strain.

FIG. 5 is an enlarged side elevation of another embodiment of a rearportion of a slider incorporating a film of deformable material.Deformable material 60 is a film or mass of low-yield-stress material.The low-yield-stress characteristics of deformable material 60 allow thematerial to be mechanically displaced with a force pressure. Suitablelow-yield-stress materials include, for example, soft, malleable metalssuch as Cu, Al, Au, Ni, Ti and alloys thereof such as AlCu alloys ormartensitic NiTi alloys. In one embodiment, low-yield-stress deformablematerial 60 is deposited between head stack 40 and slider body 36 atinterface 42. To reduce pole tip recession 50, mechanical force isapplied at force point 68 in one embodiment. The material of head stack40 is sufficiently bonded to deformable material 60 so that transducerportion 38 does not shear off from slider body 36 at interface 42 whenforce is applied at point 68.

FIG. 6 is an enlarged side elevation view of the embodiment of FIG. 5after deformation. Prior to applying a deformation force, slider body 36should be mechanically constrained from displacing or rotating duringthe force application and removal steps. It is expected that materialssuch as metals with large grain sizes will work especially well. It ispreferable that the low-yield-stress characteristics are not so low thatfatigue or high temperature causes further unwanted adjustment. Theforce applied at point 68 causes the bulk of transducer portion 38 toexperience elastic deformation; however, the low-yield-stress deformablematerial 60 experiences a permanent, plastic deformation that will notrecover on unloading. Some materials 60 will experience a slight recoilupon unloading; in those cases, the force applied at point 68 should“overpush” to accommodate for such recoil. Force applied at point 68thereby leads to the displacement of the entire transducer portion 38with respect to slider body 36. In some embodiments, about 200 to about1,000 Pascals of pressure are applied.

After the load is released, the displacement remains, as illustrated inFIG. 6. This sliding displacement pushes head stack 40 and transducer 44downward to effectively reduce or eliminate pole tip recession andthereby result in a mechanical close point of slider 20 at or near poletip 46. A result is that the mechanical close point height 56 is equalto pole tip fly height 58. Thus, transducer 44 is desirably flying asclose to disc surface 24 as possible. As can be seen, pole tip recession50 and head stack recession 52 no longer affect pole tip fly height 58.Therefore, the invention adjusts the position of pole tip 46 tocompensate for pole tip recession 50.

FIG. 7 is a side elevation view of an enlarged portion of a sliderwherein the pole tip protrudes from the head stack but does not recedefrom the slider body. In some cases, pole tip recession is not an issue;this is the case, for example, when the lapping durability of thematerial of slider body 36 is not as great as the lapping durability ofthe material of pole tip 46. Such a case is illustrated in FIG. 7. Inthis case, a more critical dimension is pole tip protrusion 70. Pole tipprotrusion 70 is the difference in height between the bottom of pole tip46 and the bottom of head stack 40 or slider body 36. While pole tip 46of slider 72 is able to fly desirably close to the surface of disc 24,pole tip protrusion 70 can lead to accidental contact between pole tip46 and the surface of disc 24. Such unintentional contact can lead torecording and writing errors as well as disc failure. Therefore, in somecases, it is desirable to decrease or eliminate pole tip protrusion 70.Because the materials of pole tip 46 are very delicate, it is generallynot advisable to force pole tip upwards from its bottom surface.Therefore, a contractible deformable material 60 can be used to pulltransducer 44 and pole tip 46 upwards with respect to head stack 40.

FIG. 8 is a side elevation view of the slider of FIG. 6, afteractivation of the deformable material. In one embodiment, deformablematerial 60 contracts in a linear direction; as it contracts, it pullsat its ends upon the attached head stack material in the directionsindicated by arrows 74 and 76. Contraction in the direction of arrow 74leads to the formation of recess 78 in a top surface of slider 72.Contraction in the direction of arrow 76 pulls transducers 44 and poletip 46 upward to eliminate or reduce pole tip protrusion 70 (shown inFIG. 7).

In one method of practicing the present invention, pole tip recession orprotrusion is measured after the wafers have been divided into bars orindividual sliders. The wafers, bars or sliders are then separated basedon their required pole tip adjustment. The level of excitation energy iscalculated for the required adjustment for each group of wafers, bars orsliders: i.e., magnetization level of permanent magnet layer,temperature and exposure time of thermal energy, intensity and exposureof laser energy, or position and amount of force application, forexample.

In the present invention, the position of the pole tip issemi-permanently adjusted during slider formation and no application ofactivation energy is required during the use of the slider to maintainthe pole tip position adjustment. When the deformable material is ashape memory alloy or low-yield-stress material, the phasetransformation induced deformation or plastic deformation retains theadjustment even after the removal of the excitation energy. In the casewhere the deformable material is magnetostrictive, its strain is held bya magnet disposed within the slider itself. While the principles of thisinvention have been described in connection with specific embodiments,it should be understood clearly that these descriptions are made only byway of example and are not intended to limit the scope of the invention.Workers skilled in the art will recognize that changes may be made inform and detail without departing from the spirit and scope of theinvention. For example, it is contemplated that the present inventioncan be used to change the distance between the bottom of the pole tipand the bottom of the head stack or slider body from any distance to anydistance. The term Adistance@ includes zero distance; for example, wherethere is no pole protrusion or recession from the head stack or sliderbody.

1. A sensor comprising: a transducer portion including asemi-permanently deformable portion positioned within the transducerportion; wherein a deformation of the semi-permanently deformableportion in response to an activation energy deforms the transducerportion; and wherein the deformation is retained after the activationenergy is removed.
 2. The sensor of claim 1 and further comprising anactive element positioned within the transducer portion, the activeelement comprising a magnetic transducing element.
 3. The sensor ofclaim 1 in which the semi-permanently deformable portion comprises a lowyield stress material.
 4. The sensor of claim 1 in which thesemi-permanently deformable portion is plastically deformable.
 5. Thesensor of claim 1 in which the semi-permanently deformable portioncomprises a shape memory alloy.
 6. The sensor of claim 5 in which thedeformation causes the semi-permanently deformable portion to changefrom a martensite crystal structure to an austenite crystal structure.7. The sensor of claim 5 in which the deformation causes thesemi-permanently deformable portion to change from an austenite crystalstructure to a martensite crystal structure.
 8. A transducer comprising:a body; an active element positioned within the body; a magnetostrictiveportion positioned within the body; a magnet having a magnetic fieldthat causes a deformation of the magnetostrictive portion; wherein thedeformation of the magnetostrictive portion in response to the magneticfield adjusts the position of the active element.
 9. The transducer ofclaim 8 in which the magnet has a coercivity between about 2 and about20 kOe.
 10. The transducer of claim 9 in which the sensor furthercomprises a reader coercivity and in which the magnet has a coercivityat least about 500 Oe greater than the reader coercivity.
 11. Thetransducer of claim 8 in which the magnetostrictive material is a rareearth transition metal alloy.
 12. A method for adjusting the position ofan active element of a transducer, the method comprising: providing abody having an active element and a semi-permanently deformable portion;and deforming the semi-permanently deformable portion with an activationenergy to adjust the position of the active element such that thedeforming is retained after the activation energy is removed.
 13. Themethod of claim 12 in which the active element comprises a magnetictransducing element and the transducer portion comprises a head stackportion containing the magnetic transducing element and thesemi-permanently deformable element.
 14. The method of claim 12 in whichthe energy is selected from the group consisting of temperature change,magnetism, voltage and pressure force.
 15. The method of claim 12 inwhich the step of deforming the semi-permanently deformable element iscompleted during manufacture of the transducer.
 16. The method of claim12 further comprising deforming the semi-permanently deformable elementto reverse the adjustment.
 17. The method of claim 12 in which thesemi-permanently deformable element comprises a low yield stressmaterial.
 18. The method of claim 12 in which the semi-permanentlydeformable element comprises a shape memory alloy.
 19. The method ofclaim 12 in which the step of deforming the semi-permanently deformableelement comprises causing a crystal structure transformation of thesemi-permanently deformable element.
 20. A method for adjusting theposition of an active element of a transducer, the method comprising:providing a transducer body containing an active element and amagnetostrictive portion; and deforming the magnetostrictive portion byexposing the magnetostrictive portion to a magnetic field to adjust theposition of the active element.